What is a Cell?

It is a basic unit of life. Larger organisms are composed of cells.

Types

There are two types of cells: $^1$

• Prokaryotic
  • May only be unicellular
  • No true nucleus
• Eukaryotic
  • May be either unicellular or multicellular
  • Has a true nucleus

There are four types of Eukaryotic cells: $^1$

• Animal
• Plant
• Fungi
• Protists

Eukaryotic Cells

Cell Organelles

Cell organelles are the parts of the cell that carry out its function.$^0$

Cell Membrane

It is a sheet-like protective surface that covers the cell. It is selectively permeable.$^0$

Ribosomes

They are small globular structures that produce proteins. They are made in the nucleus and are of two types. Free ribosomes roam around the cell producing proteins for the cell. Membrane bound ribosomes are attached to the RER and produce proteins for external(outside of the cell) use.$^0$

Nucleus

Nucleus contains the DNA of the cell.$^0$